After providing dedicated and consistent care to get your lawn looking its best, it can be disheartening not to see optimal results.
It can be difficult to understand why this is the case, but it may be due to an undiagnosed lawn fungus or disease.
These common garden issues can often go undetected until they have caused significant damage to your lawn.
In this guide, we will cover everything you need to know about identifying common symptoms of lawn disease, the different types, and how to prevent and treat them to maintain a healthy lawn.
What are lawn diseases?
Lawn diseases are conditions caused by pathogens, generally fungi, which attack your lawn and deprive it of vital nutrients.
However, it is important to know that not all fungi are diseases, and some can actually be beneficial for your lawn by breaking down organic material.
Fungi usually lose their beneficial qualities under less favourable conditions like poor soil quality, excessive moisture, and extreme temperatures.
What causes lawn diseases?
Now that you are aware of what lawn diseases are, it is time to take a closer look at what causes these issues.
Understanding how lawn fungus and disease start is the first step to effectively managing them and preventing their return in the future.
Here are some of the most common causes of lawn disease:
- Drought. Lack of water and hot temperatures can put stress on your lawn, weakening it and leaving it more vulnerable to disease
- Excessive moisture. Whether it is overwatering, heavy rainfall, or humidity, excessive moisture creates the perfect damp conditions for fungal growth to thrive
- Seasonal changes. Different seasons are favoured by certain diseases. For example, Snow Mould thrives in cooler temperatures, while lawn diseases like Dollar Spot and Rust prefer the warmer temperatures of Spring and Summer
- Cutting grass too short. Scalping your lawn leaves it exposed to both pests and diseases, so always ensure that you never take off more than one-third of the grass at a time
- Compacted soil. Prevents nutrients, airflow, and water from reaching your grass roots, allowing lawn fungus to take over
- Thatch build-up. Thatch is the perfect breeding ground for diseases and fungi, as it is damp and moist
- Over or under-fertilizing your lawn. A common lawn care error that can be extremely damaging to your lawn, especially when it comes to diseases. Over-fertilizing can cause rapid but weak growth while under-fertilising leaves your grass without the essential nutrients it needs to fight off diseases
What are the symptoms of lawn disease?
Recognising the symptoms of lawn disease is crucial to taking action and ensuring it does not spread and cause further damage.
Symptoms can vary depending on the type of disease; however, there are common signs to look out for that can indicate that your lawn is suffering.
Here are some of the key symptoms to look out for:
- Discolouration. Brown or yellow patches on your lawn are one of the most common signs of lawn disease. Patches indicate weakened grass that is under stress and is lacking in vital nutrients
- Bare patches. Diseases can make it very difficult for bare patches to recover, even if you have overseeded and provided dedicated care. The disease will need to be dealt with effectively before recovery can begin
- Rust spots. Look closely at your grass blades, as diseases like Rust can cause orange, yellow, or brown spots to appear
- Circular or irregularly shaped spots. Certain diseases like Brown Patch and Dollar Spot will form distinct patterns
- Mushrooms and fungus. The appearance of mushrooms or toadstools can indicate the presence of disease in your lawn
What is the most common grass disease?
Red Thread is one of the most common lawn diseases found in gardens throughout the UK.
It causes patches of dead grass to appear on lawns, generally in late summer and autumn during wet conditions.
Other common types of lawn disease in the UK are:
- Fusarium Leaf Spot
- Snow Mould
- Rust
Common types of lawn fungus and diseases
To ensure that you are fully equipped to protect your lawn against fungus and diseases, it is essential that you know how to spot them.
Some diseases can have similar symptoms that make them more difficult to distinguish.
Here are some of the most common lawn diseases, their symptoms, and how you can treat them:
1. Red Thread
| Characteristics: Red or pink thread-like strands appear on grass blades, especially during humid conditions. This common lawn fungus takes advantage of lawns with nutrient deficiencies and can spread quickly. If Red Thread is not dealt with effectively, it can spread and gradually weaken your lawn, making it more susceptible to other diseases. Occurrence: Generally, occurs in cool and damp weather Treatment: To rid your lawn of this disease, you will need to apply a nitrogen-rich fertiliser to replenish lost nutrients and strengthen your lawn. After applying your fertiliser, ensure that the soil receives regular water to avoid it drying out. Within a few days, you should be able to rake out the dead remains of the fungus and aerate your lawn to improve airflow and nutrient absorption. |
2. Dollar Spot
| Characteristics: If your lawn is suffering from Dollar Spot, you might find small, circular patches littering your lawn. Patches can differ from being white/straw coloured or light brown surrounded by a darker boarder. Occurrence: Dollar Spot tends to thrive in warm and humid conditions Treatment: Similarly, Dollar Spot can be effectively treated by feeding your lawn with a nitrogen-rich fertiliser, as this will address any deficiencies. Alternatively, you can spread lime if your soil is too acidic, as this will help to balance out the pH and create an environment that works against fungal growth. However, if you are still finding that the fungus will not budge, you should apply an organic fungicide that is specially formulated to combat Dollar Spot. |
3. Rust
| Characteristics: Rust is one of the slower-acting lawn fungi and makes its appearance known with yellow and orange spots on grass blades. In addition, it can leave a powdery residue on shoes after you have walked on your lawn. Rust tends to target lawns that are thin, weak, and undernourished, and if not dealt with promptly, it can spread quickly. Occurrence: Rust can appear at any time of the year, but it does favour warm, wet, and humid conditions Treatment: Ensure you apply the correct amount of fertiliser to your lawn; ideally, you should use a high-potassium fertiliser in autumn and high-nitrogen in spring. In addition, you will also want to regularly mow your grass to remove the affected leaves and remove the clippings once finished. The key to treating rust is prevention, which all starts with providing consistent care to your lawn. |
4. Snow Mould
| Characteristics: Snow Mould appears on your lawn in white, fluffy patches, mimicking the appearance of snow. Initially, the patches will start off quite small at a few centimetres in diameter but will eventually spread to approximately 30 cm. Occurrence: This lawn fungus favours cool weather, as it provides the perfect conditions for it to spread rapidly. It will come as no surprise that Snow Mould develops under prolonged blankets of snow, particularly when lawns have poor drainage or thatch. You can usually only identify the damage caused by Snow Mould once the snow has melted. Treatment: We recommend prevention as the best course of action for protecting your lawn against Snow Mould. Loosen the soil surface by aerating or scarifying your lawn to aid airflow as soon as possible. In addition, you should avoid applying a high-nitrogen fertiliser in late autumn, as this can encourage fungal growth during winter. For more advice on how you can get your lawn winter-ready, check out our autumn lawn care guide. |
5. Powdery Mildew
| Characteristics: Mildew causes a white/grey fluffy coating to appear at the top of your grass blades. If you look closely, you will see black dots within the fluffy coating, which are the fungal spore structures. Powdery Mildew feeds off the grass tissue, causing your lawn to become dehydrated, stunt its growth, and eventually die. Occurrence: Powdery Mildew is another lawn disease that favours cool, humid conditions. It commonly sprouts up in the most shaded areas of your lawn or those that have poor circulation. Treatment: Following a good lawn care schedule can prevent Powdery Mildew from appearing on your lawn. We recommend planting in full sunlight when possible and keeping overhanging trees or bushes regularly trimmed so more sunlight can reach your lawn. In addition, aerating your lawn can remove any excessive thatch, reducing the risk of humidity and poor air circulation. You should also ensure that you are regularly mowing your lawn to a healthy height and watering as needed. Finally, if the problem persists, you should apply a sulphur-based fungicide that will create an unfavourable environment for the fungus to thrive. |
6. Fairy Rings
| Characteristics: Fairy Rings can appear on your lawn in three different ways: – Dark, brown grass rings – Dark green rings – Mushroom/toadstool rings Although the name might sound charming, this fungus creates a waterproof layer over the soil surface that deprives your lawn of vital nutrients. Lack of nutrients, water, and air will cause your grass to turn brown and produce dead grass rings. Occurrence: Fairy Rings often occur in spring and autumn, during humid and wet weather. They are more common in lawns that have a high level of organic material, such as leaves or thick thatch layers. Treatment: To treat Fairy Rings, you will want to promptly dethatch and aerate your lawn to remove any dead organic matter and promote airflow to the soil. After dethatching, you should apply a fine layer of high-quality lawn sand, which will improve soil structure, encourage deeper root growth, and dilute any organic material remaining in the soil. If your lawn is suffering from dark green Fairy Rings, you should apply a high-nitrogen fertiliser to reduce the appearance of circles. For brown or dead rings, we recommend aerating the soil |
7. Root Rot
| Characteristics: Root Rot, otherwise known as Pythium Lawn Disease, will show itself as sunken, brown areas on your lawn. In addition, it coats your grass blades with a slimy film, which can help the fungus to spread to other healthy areas of your lawn. Root Rot commonly affects vulnerable lawns with poor drainage and compacted soil. Occurrence: This common lawn fungus usually appears in summer or autumn when temperatures are humid or damp. Treatment: Ideally, the first thing you should do when signs of root rot make themselves known is aerate your lawn. Aerating will loosen the soil and alleviate any compaction caused by thatch or other decomposed organic matter. Following this, you should remove any thatch with a rake to prevent further build-up. Root Rot is caused by waterlogging, so it is important to adjust your watering schedule and water early in the morning so your lawn can dry throughout the day. |
How to prevent lawn fungus
Preventing lawn fungus and disease does not have to be difficult; in fact, it could not be simpler.
All you need to do is focus on providing your lawn with a good level of maintenance consistently.
By doing this, you will not only reduce the chances of potential risks but also create a healthy and resilient environment where fungal diseases cannot thrive.
Here is what you can do to prevent lawn diseases and fungi:
- Water to the conditions. Generally, we recommend deeply watering your lawn once or twice a week to promote strong root growth. However, it is always worth checking the weather forecast so you can avoid overwatering if rain is expected
- Mow properly. Ensure you are never removing more than a third of grass height per mowing session. If you remove more, you are at risk of scalping your lawn, which causes stress and makes it more vulnerable to disease
- Aerate and detach regularly. Aerating your lawn is a great way to relieve compaction, allowing water to drain properly and nutrients to reach your grass seeds. In addition, you should regularly remove any excess thatch, as this can become a breeding ground for fungal spores
- Ensure your lawn has light. Try to make sure your lawn has as much light as possible, as this can help to dry out any excess moisture from the soil surface
- Fertilise appropriately. Use our expertly formulated Perfect Prep Fertiliser, which has been blended with the correct balance of nitrogen, phosphorus, and potassium your lawn needs to thrive. For seasonal nourishment, you can also ensure your lawn has all it needs with our Spring, Summer, Autumn, and Winter Fertilisers.
- Monitor your lawn. Regularly check your lawn for any changes or signs of disease/fungus. Catching them quickly can help to address the problem sooner and reduce the damage to your lawn
FAQ’s
What does grass with fungus look like?
This entirely depends on the disease or fungus that has decided to call your lawn home.
However, there are some common signs of lawn fungus you can look out for, such as:
- Yellow, brown, or orange patches
- Powdery coatings
- Yellow or orange spots on grass blades
- Pink or red threads on grass
- Slimy or mouldy patches
- Dark or brown circular patches
If you spot any of these symptoms, it can be a key indicator of lawn disease, so you should act promptly.
What disease turns grass brown?
There are a few different lawn diseases that can cause your grass to turn brown and produce dry patches.
These include:
- Brown Patch
- Dollar Spot
- Rust
- Root Rot
These diseases work by depriving your grass of air, water, and the nutrients it needs, causing it to weaken, thin, and become discoloured.
Will grass grow back after fungus?
Yes, in general, lawns can recover well from fungal damage; however, this can depend on the severity of the disease and how quickly the problem was addressed.
In mild cases, it is possible for grass to recover within a matter of weeks with the right amount of care.
For more severe cases, recovery can take months, and you may need to reseed your lawn to repair extensive damage.
If you do need to reseed or overseed your lawn, you can use our specialised Thick & Thriving Grass Seed Mix that promotes rapid germination, resulting in a dense and resilient lawn.
Ready to rid your lawn of disease?
It can be disheartening to find that your lawn is suffering from fungal diseases, but do not worry.
By treating the problem quickly and following good lawn care maintenance practices, you can restore your lawn back to full health in no time.
Start your lawn’s journey back to health and take our quiz today to be matched with your perfect bundle!
